Disinfestation Process

ABSTRACT

Process for controlling the development of parasites in an animal environment equipped with an air introduction device, according to which a parasiticidal powder composition is introduced into the air introduction device, preferably according to which the air introduction device comprises one or more point(s) of introduction of air into the animal environment located close to the animal droppings. The invention also relates to the use of the process, to the use of a parasiticidal composition in an air introduction device for controlling the development of parasites in an animal environment, to a device for controlling the development of parasites in the animal environment, and to a livestock building equipped with such a device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. national stage entry under 35 U.S.C.§371 of International Application No. PCT/EP2012/058949 filed May 14,2012, which claims priority benefit to French patent applications FR11.54102, filed on May 12, 2011 and FR 11.54773, filed on May 31, 2011,the whole content of each of these patent applications being hereinincorporated by reference for all purposes.

TECHNICAL FIELD

The invention relates to a disinfestation process. The invention relatesmore particularly to a process for disinfesting the environment ofanimals by introducing a parasiticidal powder composition into theaeration device of the said environment. The invention also relates to adevice for controlling the development of parasites in the environmentof animals, and to a livestock building equipped with such a device.

The term parasiticidal composition means a composition on contact withwhich the parasites that tend to develop especially on livestockanimals, pets or man cannot survive.

The term “parasites” means arthropods such as insects, mites, fleas,flies and ticks.

The parasites may be in the egg, larval or adult stage. The action ofthe composition may be direct. It may also be indirect, for example whenthe parasiticidal composition destroys a substance necessary to thesurvival of the parasite.

TECHNICAL BACKGROUND

The development of parasites on livestock and pets is a well-knownworrying problem. It may have major consequences on hygiene and thepropagation of certain diseases in the case of livestock rearing, suchas: salmonellosis especially in aviculture, enterocolitis, verminosis,mastitis and keratoconjunctivitis in cattle, foot-and-mouth disease,swine fever, erysipelothrix infection and myxomatosis in rabbits. Thisdevelopment may have major consequences on the economic productivity ofthe livestock business, especially in aviculture, and in particular onthe rearing of table chickens, and turkeys, and laying hens.

It is especially known practice to combat parasites using neurotoxicsubstances and growth inhibitors such as synthetic pyrethroids,organophosphorus compounds or carbamates, for example. These productsare applied either by spraying or by thermo-nebulization. Their usesare, for the vast majority of the products, prohibited in the presenceof animals. The reason for this is that these substances have thedrawback of also being toxic to the animal on which the parasitesdevelop. Some of these substances also have an allergenic nature to manor animals. When the rearing of the animal is intended for human foodconsumption, the use of neurotoxic parasiticidal agents is prohibitedsince these substances contaminate the food chain, as stated in theEuropean directives on biocides (98/8 EC) and on plant protection(91/414 EEC). It also presents risks to the breeders.

It is also known that parasiticidal compositions based on natural orsynthetic essential oils or on pyrethroids or on organophosphoruscompounds used as alternatives to organochlorine compounds have anefficacy that decreases rapidly over time. These parasiticidalcompositions have an action that may be termed a “shock action”. Theirefficacy is generally of the order of a few days, and at most of theorder of a few weeks. This is due to non-zero vapor pressures of thecomponents that give rise to their volatilization over time and moreoverto their degradation by oxidation.

Parasites that have been eliminated at one particular moment mayreinfest a livestock unit in the course of livestock production. Thetoxicity of such compositions, including their toxicity to animals,limits their use on occupied buildings.

Patent WO 01/35744 discloses a parasiticidal composition based onsilica. This composition in gel form is free of neurotoxic substances,but is expensive. The composition is not a powder but a granular systemwhich solid particles are surrounded by a liquid phase and behaves as aliquid, as it forms a horizontal surface in a recipient. The aerated gelcomposition, comprising gelling agent and high amount of water, sticksstrongly on treated surfaces. This is an interesting property to fix thesilica on treated surfaces but presents the drawback of forming on thetreated surface a gelatinous deposit onto which also ambient dust has atendency to adhere, which reduces its efficacy over time.

Patents WO 2005/025 317 and WO 2006/097 480 disclose variousparasiticidal compositions in the form of aqueous suspensions based onan alkali metal bicarbonate, which have the advantage of not being toxicto man and animals. These compositions are applied by brushing orspraying onto the vertical surfaces of the buildings and equipment to betreated. The treatment of a livestock building, for example for rearinglaying hens, after sanitary cleaning and mucking out, is usuallyperformed by spraying with suspension. However, the operation requiresspecific low-pressure or high-pressure industrial spraying machineswhich represent a certain investment, and the operation requires severalhours to apply the aqueous suspension to all the surfaces of the cagesand those close to the feeding troughs. The drying of the aqueoussuspensions is itself effective within a few minutes to a few hoursdepending on the applied thickness.

Patent WO 2006/097 504 discloses a parasiticidal composition in powderform based on an alkali metal bicarbonate, which may be applied bydusting onto the horizontal surfaces of buildings occupied by livestockon the ground. Here also, the treatment of ground surfaces requiresseveral hours of work when large surfaces such as those of livestockbuildings need to be treated, despite the use of specific equipment.Moreover, the floor is often made of slotted floorings or gratings,through which the animal droppings fall. When these slotted flooringsare covered with product in powder form, the animals walking on theseslotted floorings remove the product from the floor; this makes regularretreatment of these surfaces necessary.

The invention is directed towards providing an alternativedisinfestation process that affords an appreciable saving both inapplication time and in investment on specific machines, which offerslasting efficacy in the control of parasites that develop on animals andin their environment.

SUMMARY OF THE INVENTION

The invention relates to a process for controlling the development ofparasites in the environment of animals equipped an air introductiondevice with at least one introduction point, according to which aparasiticidal powder composition is introduced into the air introductiondevice. The invention also relates to the use of the process.

In the present document a powder means a granular media made of solidparticles and surrounded by a gaseous phase, which is the commondefinition of a powder. As for instance, a suspension of solid particlesin a liquid is not a powder as the solid particles are surrounded with aliquid phase. One characteristic of a powder is that its surface doesnot move to a flat horizontal surface in a non agitated container,contrary to a liquid that moves to a flat horizontal surface, whateverthe inclination of the container.

The invention also relates to the use of a parasiticidal powdercomposition in an air introduction device for controlling thedevelopment of parasites in an animal environment.

The invention also relates to a device for controlling the developmentof parasites in the environment of animals, and to a livestock buildingequipped with such a device.

A first advantage of the present invention is an important gain in timeand operator costs to treat large area of a livestock building comparedwith known prior art.

A second advantage of the present invention is a strong reduction of thequantity of parasiticidal powder composition used per animal compared toknown prior art.

A third advantage of the present invention is the possibility to use asafe parasiticidal powder which main components are compatible with foodindustry requirements.

A fourth advantage of the present invention is the possibility to use asafe parasiticidal powder which main components are also food chemicalcodex additives and also meet regulations such as 889/2008 EC Europeandirective on organic production and labelling of organic products.

A fifth advantage of the present invention is to decrease risks for thehealth of breeders and workers as embodiments of present inventionreduces concomitantly the quantity of parasiticidal composition to applyin animal environments, reduces sharply the toxicity of theparasiticidal composition, and also enable to workers to be out of theanimal environment when proceeding to a treatment.

A sixth advantage of the present invention is to be efficient on largescope of parasites and pests such as acarids, crawling insects, flyinginsects, and fungi.

A seventh advantage for specific embodiments of the invention, is toleave on droppings of animals in treated environments useful componentas alkali bicarbonate, when the animal droppings or manure are furthervalorized in Biogas production.

DETAILED DESCRIPTION OF THE INVENTION

Buildings in which animals are present, in particular rearing buildings,must ensure an air renewal and adequate indoor temperature for theanimals. In particular air introduction enables to maintain an indoorair renewal, a temperature, a humidity level, a level of dust and gasconcentrations in adequate levels in the animal environment for theirhealth. Regulations, such as the 1999/74/EC European directive forlaying hens, lay down minimum standards for the protection of animals,to keep a balance between welfare and health of the animals andeconomic, social and environmental considerations. The handling andstorage of animal manure or droppings in an animal environment may needalso air introduction for sanitary reasons; In particular cases,specific air introduction is used to dry partially droppings and/ormanure, particularly when mechanized evacuations devices are used instables or in rearing buildings.

In the present invention, the device for introducing air into the animalenvironment is a device suited for transporting the parasiticidal powdercomposition into the animal environment. This device may be chosen fromone of the following devices: aeration grille, air capacity underpressure, forced motorized ventilation, and combinations thereof.Aeration grille, forced motorized ventilation, and combinations thereofare preferred.

In one advantageous embodiment of the invention, the aeration grille isa grille placed on a building wall associated with one or more secondaryaeration grilles, arranged such that the outdoor air flow passingthrough the aeration grille into the animal environment has a sufficientvelocity to entrain a parasiticidal composition in pulverulent powderform. The outdoor air may be taken directly outdoor of the animalenvironment, or taken from another part of a building if adequate torenew the air.

In another advantageous embodiment of the invention, the airintroduction device is an airing device comprising at least oneappliance that forces the airing of the said environment, and accordingto which the parasiticidal composition is introduced upstream ordownstream the at least one appliance that forces the airing, preferablyupstream the at least one appliance that forces the airing. Theappliance that forces the airing may be chosen from equipment known tothose skilled in the art, such as electrical, pneumatic or mechanicalmotor-driven fans. In particular, it may be chosen from fans, turbofansand ejectors. Fans are particularly suitable.

The above embodiments are particularly advantageous when the airintroduction device is a permanent ventilation device of the animalenvironment. In the present description, the term “permanent ventilationdevice” means a ventilation device that is permanently fixed to theanimal environment, for instance fixed to a stable or to a rearingbuilding. Examples of permanent ventilation device are: building ventingdevices or systems, and/or devices aiming at drying partially the animaldroppings. The use of a permanent ventilation device in the presentinvention enables to use part of the existing equipments of suchbuildings, reducing therefore the cost and the investment to use presentinvention. The permanent ventilation device may not be used permanently,or may be used at variable air flows, according to the seasons andindoor air conditions to maintain, though it can be turned on whenapplying the parasiticidal powder composition.

The permanent ventilation device also often includes a heater and/or acooler to maintain indoor air temperature in adequate levels for theanimal. The possibility to heat the air introduced with the permanentventilation device in the cold season enables to desaturate theintroduced air regarding humidity if outdoor air is close to its dewpoint temperature. Such heating device decreases the risk that theparasiticidal powder composition sticks on the air introduction device,for instance on ventilation forcing equipments and air ducts if humiditycondenses on such equipments. Typical air-flows generated by airintroduction device ranges:

-   -   from 1 to 5 m³/h per kg of animal for a barn or a rearing        building venting device,    -   from 0.5 to m³/h per kg of animal for a device aiming at drying        partially the animal droppings.

According to one recommended embodiment of the invention, the airintroduction device comprises one or more point(s) for introducing airinto the animal environment, which is(are) located close to animaldroppings. In the present invention, the term “close to the animaldroppings” means a distance preferably not more than 10 meters, morepreferably not more than 5 meters, or even not more than 2 meters andmost preferably not more than 1 meter. In one even more recommendedembodiment, the point(s) of introduction of air into the animalenvironment are placed in immediate proximity to the transporters orbelts for removing the animal droppings. In another recommendedembodiment the air introduction device is a device aiming at dryingpartially the animal droppings. In the case of livestock in a cage, suchas that of laying hens, it is particularly advantageous for the airintroduction device to be the device for drying the droppings located onthe belts, which are themselves under the lower grilled part of thecages.

In any of the above embodiments, the parasiticidal powder compositionconsists of particles, in which said particles preferably have aparticle size distribution such that at least 75% in weight of theparticles have a diameter of less than 100 μm and more preferably suchthat at least 90% in weight of the particles have a diameter of lessthan 70 μm. The diameters are measured according to standard ASTMC-690-1992. Such a form of the parasiticidal composition enablesefficient diffusion of the parasiticidal composition by the airintroduction device into the animal environment. The parasiticidalcomposition is then dusted as a fine layer in the animal environment.The parasites moving in contact with the parasiticidal compositioncannot then survive.

In one advantageous embodiment of the invention when the airintroduction device is an airing device comprising at least oneappliance that forces the airing of the said environment, theparasiticidal powder composition is introduced gradually into the airingdevice by means of a mechanized or a manual device. The mechanizeddevice may be chosen from bottomless hoppers, screw-feed solid meteringdevices, hopper devices equipped with a rotary trefoil, hopper devicesequipped with slide-gate valves, conical hopper devices equipped withknife-edge mixer-feeders, and combinations thereof. The manual devicemay be chosen from bottomless hoppers, funnels, buckets, troughs,metering cups, metering shovels, and combinations thereof. The powder isthen introduced gradually into or via the said device over a time of atleast one second, or at least 2 seconds, or of at least 5 seconds, or ofat least 10 seconds. In one particular mode of this advantageousembodiment, the powder is introduced into the said device continuously,or preferably over a time of not more than 10 minutes, more preferablynot more than 5 minutes, or more preferably not more than 1 minute.

In any one of the above embodiments, the parasiticidal compositionadvantageously comprises an alkali metal bicarbonate and/or silica.

In the process according to the invention, the alkali metal bicarbonatemay, for example, be bicarbonate in the strict sense such as potassiumbicarbonate or sodium bicarbonate. However, in this document, it alsocovers compound salts such as alkali metal sesquicarbonates (for exampletrona) which comprise bicarbonate. Sodium or potassium bicarbonates ortrona are especially suitable for use. Bicarbonates in the strict senseare recommended. Potassium bicarbonate or sodium bicarbonate, moreparticularly sodium bicarbonate, are preferred. In certain cases,however, potassium bicarbonate is more preferred.

In the particular embodiment of the present invention, in which theparasiticidal powder comprises an alkali metal bicarbonate and/orsilica, the powder advantageously comprises at least 60%, preferably atleast 70% and even more preferentially at least 80% by weight ofbicarbonate. Bicarbonate has its own parasiticidal action.

In the particular embodiment of the present invention, in which theparasiticidal composition in powder form comprises an alkali metalbicarbonate and/or silica, the parasiticidal composition comprises atleast 1% and preferably at least 5%, more preferably at least 10% byweight of silica. The amount of water, as humidity or as water moleculesinside in the parasiticidal composition, has an impact on theflowability of the powder. Moreover a high amount of water gives rise tohigh adhering properties of the powder to the surfaces of the airintroduction device. This may leads to plugging of air ducts andunbalance rotation of rotating devices such as fan. In present inventionit is recommended that the parasiticidal powder composition comprisesless than 30%, advantageously less than 25%, more advantageously lessthan 20%, preferably less than 10%, more preferably less than 5%, evenmore preferably less than 3%, most preferred less than 2% in weight ofwater.

When silica is combined with alkali metal bicarbonate, it is recommendedthat the parasiticidal powder composition comprises at most 20% andpreferably at most 15% thereof.

In present invention when the parasiticidal comprises silica, the silicapreferably comprises less than 4 w. % of crystalline silica, morepreferably less than 0.1 w. % of crystalline silica. Mineral compoundscomprising silica (SiO₂) such as diatomaceous earth, preferably noncalcined diatomaceous earth, or clays such as bentonite, may be used.Non calcined diatomaceous earth comprises generally between 0.1 and 4 w.% of crystalline silica. Though it is recommended that the silica be inamorphous form (and not crystalline) for its tolerance by the human oranimal body. More preferably in present invention the parasiticidalpowder composition is free of diatomaceous earth. And even morepreferably the parasiticidal powder composition is free of crystallinesilica.

It is preferable for the silica to be in the form of very fineparticles, with a high specific surface area, for example greater than200 m²/g and preferably 400 m²/g, measured according to standard ISO5794-1, annex D. In one advantageous embodiment of the invention, thesilica is in the form of particles with a mean diameter of less than 10μm. The mean diameter is measured according to standard ASTM C-690-1992.

Amorphous silica is a silica that is nutritionally neutral, and is acompound registered on the list of mineral products of the CodexAlimentarius of the FAO (Food and Agriculture Organization) and of theWHO (World Health Organization).

It has been observed that when the parasiticidal composition is inpowder form and simultaneously comprises an alkali metal bicarbonate anda silica, the powder has excellent fluidity. It generates virtually nobonding or adhesion of powder to the walls of the introduction device.Specifically, synergism between the two components of the powder iscreated: the silica affords very good flowability to the powder, and thealkali metal bicarbonate affords a light abrasive effect of the powder,bringing about a self-cleaning effect on any powder deposits in the airintroduction devices.

The parasiticidal powder may comprise essential oils for their knownparasiticidal effects, specifically neurotoxic effects for insects.Though high amount of essential oils are detrimental to powder fluidityand glues the powder to surfaces such as air ducts. Moreover essentialoils are irritating for eyes or respiratory organs of human and animals.Therefore the parasiticidal powder composition in present inventioncomprises advantageously less than 5%, preferably less than 2%, morepreferably less than 0.5% in weight of essential oils; even morepreferably the parasiticidal powder composition is free of essentialoils.

In any one of the above embodiments, the parasiticidal powdercomposition is advantageously free of neurotoxic substances.

In another particularly advantageous embodiment, when the parasiticidalcomposition comprises an alkali metal bicarbonate and/or silica, theparasiticidal composition is free of parasiticidal active ingredientsother than silica and alkali bicarbonate. Specifically, alkali metalbicarbonates and silica are substances that are not harmful to man oranimals. In the case of sodium and potassium bicarbonates, they arepermitted by various bodies (such as the Food and Drug Administration inthe United States and the EEC, the Food and Agriculture Organization,and the WHO) in human and animal nutrition. In this particularlyadvantageous embodiment, the alkali metal bicarbonate is preferablysodium bicarbonate.

The process according to the invention is effective against parasites innumerous animal environments, including certain human environments. Theterm “environment” means all the surfaces on which the parasites mayalight, move around or develop. This environment includes, for example,the floors of dwellings, caves, lofts or livestock buildings, thesebuildings comprising cages, laying nests, boxes, litters and beds.

The parasites that develop on livestock are extremely varied: fleas,lice, bugs and ticks are especially encountered. The process accordingto the invention is used in the animal environment to control thedevelopment of insects such as fleas, lice and beetles, and thedevelopment of mites such as ticks and sarcoptics. According to oneadvantageous variant of the process according to the invention, theparasites are mites. The process is especially effective againstDermanyssus gallinae. These parasites have a tendency to developabundantly in the environment of laying hens. They are intermittentparasites. They do not always remain on contact with animals. They arekilled upon contact with the animal's treated environment.

Livestock buildings also suffer from the presence of numerous molds andfungi of various types, for instance Aspergillus, especially fumigatus.The use of bicarbonate in the parasiticidal composition according to theinvention also makes it possible to combat their development.Consequently, the invention also relates to the use of the processaccording to the invention for its combined parasiticidal and antifungaleffects.

The process according to the invention may be used for controlling thedevelopment of parasites in the environment of any type of livestock.Examples that may be mentioned include cattle, sheep, goats, rabbits,poultry, birds and pigs. Disinfestation of their environment improvesthe growth and development of these animals, and increases theproductivity of the livestock. Consequently, according to onerecommended embodiment of the process according to the invention, theanimals are livestock and the environment is in particular the buildingin which the animals are reared.

According to one recommended embodiment of the process according to theinvention, the livestock is poultry, such as laying hens, or tablechickens and turkeys. It has been observed that the treatment accordingto the invention of their environment allows good egg production bylaying hens and good growth of the hens, by virtue of the elimination ofthe parasites.

The process is particularly advantageous for the rearing of laying hens.Specifically, the process according to the invention allows effectivecontrol of the development of red mites, such as Dermanyssus gallinae,which are vectors for the transmission of certain types of salmonellosisthat may attack the eggs and that are, moreover, liable to degrade thevisual quality of the eggs by generating marks on the surface of theeggs.

When the parasiticidal composition comprises an alkali metal bicarbonateand/or silica, the parasiticidal composition is introduced into the airintroduction device in an amount per application of at least 5,preferably of at least 10, more preferably of at least 20 and mostpreferably of at least 40 mg per kg of animal. It is not necessary tointroduce the parasiticidal composition into the air introduction devicein an excessive amount, otherwise the animal environment will be madedusty and slippery. It is recommended to introduce the parasiticidalcomposition into the air introduction device in an amount perapplication of at most 2000, preferably at most 500, more preferably atmost 125 and most preferably at most 80 mg per kg of animal.

According to the process of the invention, it is moreover recommendedfor the frequency of application of the parasiticidal composition to beat least every two months, preferably at least monthly, more preferablyat least fortnightly and most preferably at least weekly.

Thus, an application in accordance with the process of the inventionrequires several tens of operator seconds to several operator minutes,which may be repeated regularly, instead of three to four operator hoursfor a traditional direct treatment of the surfaces by dusting orspraying under pressure of a parasiticidal agent or insecticide.

Moreover, the amount of parasiticidal composition in powder form remainslimited. Thus, at a rate of 75 mg of powder per hen and per weeklyapplication, the amount of parasiticidal composition is limited to 4 gof powder per hen and per year. At a rate of 100 mg of powder per henand per weekly application, the amount of parasiticidal composition is 5g of powder per hen and per year. For animals reared in slow-growingconditions avoiding intensive rearing methods, and reared for less thanone year (for instance 81 days chicken, 49 days Pekin ducks, 140 daysmale turkey, 150 days capons, 6 months pigs or small ruminants) theamount of parasiticidal powder used therefore reported to an animal andnormalized according its weight is even less compared to prior art. Forinstance in prior art when a parasiticidal composition is to be used at7 g per hen in a first treatment, then renewed after one week at 7 g,and then renewed every 3 or 4 months at 3 g per hen, the total annualquantity in this case is about 25 g+/−2 g per hen and per year. Incomparison, 4 or 5 g per hen and per year are typically used in thepresent invention.

Such small amounts of parasiticidal powder per treatment, usingpreferably 5 to 80 mg of parasiticidal powder per kg of animal, enablealso to decrease temporary pick dust concentration when theparasiticidal powder is applied in the indoor air of the animalenvironment to levels, and also the amount of residual dust indoor. Itis observed that when treated with quantities of at most 2000, or atmost 500, or at most 125, or at most 80 mg per kg of animal, the animalenvironment is particularly less dusted compared to prior art using forinstance 7 g per hen of parasiticidal powder treatments; though withexcellent results in parasite control.

In a particularly advantageous embodiment of the present invention, theparasiticidal powder composition comprises at least 1% silica, and atleast 60% alkali bicarbonate, preferably at least 60% sodiumbicarbonate, and less than 30% of water, and the parasiticidal powdercomposition consists of particles, in which said particles have aparticle size distribution such that at least 75% in weight of theparticles have a diameter of less than 100 μm, wherein the airintroduction device comprises at least one point for introducing airinto the animal environment which is located close to animal droppings,and wherein the parasiticidal powder composition is introduced into theair introduction device in an amount per application of at least 5 mgand at most 2000 mg per kg of animal, and the frequency of applicationof the parasiticidal composition is at least every two months.

Consequently, the present invention also relates to the use of thepresent process for controlling the development of parasites in ananimal environment in any one of the embodiments described above.

Consequently, the invention also relates to the use of a parasiticidalcomposition in an air introduction device for controlling thedevelopment of parasites in an animal environment in any one of theembodiments described above.

The invention also relates to a device for facilitating the use of theprocess according to the invention. According to one of the embodiments,the device for controlling the development of parasites in an animalenvironment comprises:

-   -   at least one air duct for introducing air, preferably outdoor        air, at at least one point of introduction in the animal        environment,    -   at least one appliance for forcing the circulation of air in at        least one aeration conduit, and preferably able to produce in        all or part of the at least one aeration conduit an air        circulation velocity of at least 0.5, preferably of at least 1,        more preferably of at least 2 and most preferably of at least 5        m/s,    -   at least one device able to introduce a parasiticidal powder        into the said aeration conduit upstream or downstream of at        least one appliance for forcing air circulation, preferably        upstream of the at least one appliance for forcing air        circulation.

In the above device, the appliance for the circulation of air flow inthe at least one air duct is able to force the circulation of air at aflow rate of advantageously at least 1 m³/h per kg of animal.

The aeration conduit may be of any shape with cylindrical or rectangularcross sections. It is made of plastics or metals. Plastics arepreferred.

The plastics that may be used advantageously consist of polyolefins(such as charged polyethylene or polypropylene), PVC or PVDF. PVC ispreferred. When the aeration conduits are made of plastic, this plasticis advantageously filled with mineral fillers in order to give itsufficient impact strength for use in industrial or agriculturalenvironments. The surface state of the aeration conduits is preferablychosen from “smooth” interior finishes. Conduit interior surface stateshaving few or no irregularities greater than 10 μm, advantageously 5 μmand more advantageously 2 μm in size are preferred. The “smooth” aspectmakes it possible to limit any attachment of the parasiticidalcomposition when it is in powder form.

The plastics that may be used for the aeration conduit areadvantageously steel and more advantageously food-grade stainless steel.Zinc-plated steel and aluminum are less favorable since they arecorrodible.

In one advantageous embodiment of the device according to the invention,the aeration conduit is equipped at the end of straight section(s) withopening device(s) allowing the passage of tools for cleaning andbrushing the interior of the straight section(s) of the conduit.

The conduit elbows are advantageously chosen from those with a largeradius of curvature; if D is the diameter of the conduit or one of itscharacteristic internal dimensions, the radii of curvature areadvantageously at least 3D and preferably at least 5D.

The connections between straight or bent sections of the conduit areadvantageously assembled by joining together and without a jointpenetrating into the conduit.

The equipment that forces air circulation in the at least one aerationconduit is chosen from fans, turbofans and ejectors. The equipment isadvantageously chosen from fans.

The device for introducing the parasiticidal powder into the saidaeration conduit is selected from bottomless hopper devices, screw-feedsolid metering devices equipped with powder storage capacity, hopperdevices equipped with a rotary trefoil, hopper devices equipped withslide-gate valves, conical hopper devices equipped with knife-edgemixer-feeders, and combinations thereof.

When the equipment for forcing air circulation is selected fromturbofans or ejectors, the device for introducing the parasiticidalpowder is advantageously placed downstream of the equipment.

When the equipment for forcing air circulation is selected from fans,the device for introducing the parasiticidal powder is advantageouslyplaced upstream of the equipment.

In the present specification, the term “downstream” means: after theequipment for forcing air circulation relative to the main direction ofcirculation of air in the device for controlling the development ofparasites in an animal environment. In the present specification, theterm “upstream” means: before the equipment for forcing air circulationrelative to the main direction of circulation of air in the device forcontrolling the development of parasites in an animal environment.

The point of introduction of air at at least one introduction point intothe animal environment of the present invention is advantageouslylocated close to the animal droppings. The air introduction point may beequipped with deflectors. Advantageously, the air introduction point(s)consist of one or more slits on the aeration conduit.

In the case of devices for laying hens and table chickens and turkeys,the point of introduction of air at at least one introduction point inthe animal environment of the present invention is advantageouslylocated under the lower grilled part of the cages. In this case,preferably, the air introduction point is located on the droppingsevacuation belt, under the lower grilled part of the cages.

The invention also relates to a livestock building equipped with adevice for controlling the development of parasites according to thepresent invention.

EXAMPLES

The following example serves to illustrate the invention. It is notlimiting and may be transposed to other animals and other types ofrearing environment.

Example 1 (in Accordance with the Invention)

A rearing building that may contain 40 000 battery laying hens isequipped with an air introduction device for drying droppings.Mechanized belts installed under the animal cages receive the droppings.Each battery has an aeration duct. The duct has a slit for introducingair at a height about 15 cm above the belts. Each day, the droppingsbelts are activated in order to advance and evacuate the droppings.

In the present example, a parasiticidal powder Bi-Protec® from thecompany Solvay Carbonate France was used. This powder is in accordancewith that described in patent EP 1 860 948 and used in Examples 1 to 5of the said patent.

Once a week, a thorough treatment based on Bi-Protec® is performedaccording to the process of the present invention. To do this, the beltsare activated to evacuate the droppings from the belts, and thecross-ventilation in the livestock building for controlling thetemperature of the building is reduced by switching off every othercross-fan and by halving the velocity of the cross-fans that remainfunctional, thus preventing the parasiticidal powder from beingevacuated out of the building too quickly, and then, over a period of 2minutes, 4.5 kg of Bi-Protec® powder are introduced into the suction ofthe fan of the air introduction device for drying the droppings. Thisamount of Bi-Protec® corresponds to 77 mg of Bi-Protec® per laying henand per week, i.e. about 40 mg per kg of animal and per week. It isobserved after treatment that the Bi-Protec® powder is uniformlydistributed in the livestock building as a fine layer on the structuresof the building, the equipment and the surfaces of the cages.Approximately one hour after the treatment with Bi-Protec®, the crossventilation of the building is switched back on.

The corresponding amount of Bi-Protec® used over a year at a rate ofonce a week according to the procedure described above thus correspondsto 4 g per laying hen.

After a few weeks of use of the process, good control of the developmentof Dermanyssus gallinae (red mites) is observed in the livestockbuilding that was initially infested with red mites: most of the redmites observed, adults or young, are dead.

After six months of use of the process in the livestock building, thisbuilding remains very clean, few or no live Dermanyssus gallinae (redmites) are observed, and similarly few or no other mite or insectparasites are observed on the structures of the building, the cages andthe laying boxes. The hens are particularly calm, especially whencompared with the usual livestock buildings or with buildings in whichthe red mites are not treated. The air introduction circuits used fordispersing the parasiticidal powder are clean.

Example 2 Comparison on Sprayability and Dispersibility of DifferentParasiticidal Compositions

In this test, parasiticidal compositions detailed in table 1, aresprayed with dry air (dew point at 0° C.) at 2 bar pressure to form ajet with an air velocity of about 14 m/s and a parasiticidal compositionweight ratio to air of about 60 w. % on standard glass microscopelamella fixed horizontally at 60 cm of the spray jet outlet. The sprayjet axis is inclined at an angle of 45° relatively to the lamellahorizontal plane.

After 30 seconds the powder sprays is stopped and the glass lamella isremoved to be examined with an optical microscope at an enlargementratio of ×5. Observations on the experiment and microscope observationsare detailed in Table 2.

For Test E to G, the cogrinding operating conditions of theparasiticidal powder preparation are the ones described in Example 1(mode 2) of FR1161937 (Solvay). For this, a 3-liter useful capacityLödige plough mixer was used to mix the powders in the desiredproportions. The mixture is then grinded on a UPZ100 Hosokawa-Alpinegrinder using a stainless steel pin-mill rotor/stator at 17 600revolutions/min, the mixture being fed in the grinder at 1.5 kg/h.

Should the disclosure of any of the patents, patent applications, andpublications that are incorporated herein by reference conflict with thepresent specification to the extent that it might render a term unclear,the present specification shall take precedence.

TABLE 1 Parasiticidal composition of Example 2. Alkaline Parasiticidalcomposition and content Silica Bicarbonate Water Test in weight percent(w %) w. % w. % w. % A Silica Sipernat 50S/Evonik (powder) >98 0 <2 BSilica Tixosyl 38AB/Rhodia-Solvay >98 0 <2 (powder) C1 Compositionaccording to example 1 3 0 96.5 of WO01/35744A1 Hydrophobe SilicaCAB-O-SIL TS270 from Cabot with 0.5% xantham gum (liquid gel). C2Composition according to example 1 70 0 29.5 of WO01/35744A1 withdecreased ratio of water to Hydrophobe Silica CAB-O-SIL TS270 from Cabotwith 0.5% xantham gum (humid powder). D Sodium bicarbonate Bicar ® 0/415 85 <0.3 Solvay 100% < 40 μm and Sipernat 50 S mixed in a Lödigeplough mixer 5 minutes (powder). E Sodium bicarbonate Bicar ® Z/ 15 85<0.5 Solvay and Tixosyl 38AB co-ground according Example 1 (mode 2) ofFR1161937 (Solvay) (powder). F Sodium bicarbonate Bicar ® Z and 15 85<0.5 Perlite 55 co-ground (same operating conditions as powder of TestE). (powder) G Potassium bicarbonate of mean weight 18 82 <0.5 diametersize distribution of 40 μm and Perlite 55 co-ground (same preparationconditions as powder of Test E). (powder)

TABLE 2 Test Comment and Microscope observation of glass lamella ofExample 2. Test Comment and Microscope observation of glass Test lamellaA Fine layer of powder particles on the glass surface. Frequentagglomerates (soft flakes) of more than 150 μm, large size span ofagglomerates. The powder does not adhere to the glass, a simple whisperblow is sufficient to remove most of the powder. B Idem A C1 Coarselayer of gel composition adhering strongly to the glass. Difficulty tospray. A whisper blow is not sufficient to remove most of the gel.Noticeable adherence of the composition on spray jet outlet. C2 Layer ofpowder adhering slightly to the glass. D Fine layer of powder particleson the glass surface. Some agglomerates (soft flakes) of more than 150μm but less than tests A and B. The powder does not adhere to the glass,a simple whisper blow is sufficient to remove most of the powder. E IdemD. Powder well dispersed on the lamella. The powder does not adhere tothe glass, a simple whisper blow is sufficient to remove most of thepowder. F Idem E G Idem E

1. A process for controlling the development of parasites in an animalenvironment equipped with an air introduction device, comprisingintroducing a parasiticidal powder composition into said airintroduction device.
 2. (canceled)
 3. The process according to claim 1,wherein said air introduction device is an airing device comprising atleast one appliance that forces the airing of said animal environment,and wherein said parasiticidal composition is introduced upstream ordownstream of said at least one appliance that forces the airing.
 4. Theprocess according to claim 1, wherein said air introduction device is apermanent ventilation device of said animal environment.
 5. The processaccording to claim 1, wherein said air introduction device comprises atleast one point for introducing air into said animal environment, andwherein said at least one point for introducing air is located close toanimal droppings.
 6. The process according to claim 5, wherein said airintroduction device is a device aiming at drying partially said animaldroppings.
 7. The process according to claim 1, wherein saidparasiticidal powder composition consists of particles, and wherein saidparticles have a particle size distribution such that at least 75% inweight of the particles have a diameter of less than 100 μm.
 8. Theprocess according to claim 1, wherein said parasiticidal powdercomposition comprises at least 1% by weight of silica.
 9. The processaccording to claim 1, wherein said parasiticidal powder compositioncomprises less than 30% in weight of water.
 10. The process according toclaim 1, wherein said parasiticidal powder composition comprises analkali metal bicarbonate.
 11. The process according to claim 1, whereinsaid parasiticidal powder composition comprises less than 5% in weightof essential oils.
 12. The process according to claim 11, wherein saidparasiticidal powder composition is free of essential oils.
 13. Theprocess according to claim 1, wherein said parasiticidal powdercomposition is free of neurotoxic substances.
 14. The process accordingto claim 1, wherein said parasiticidal powder composition is free ofother parasiticidal active ingredients other than silica and alkalibicarbonate.
 15. The process according to claim 1, wherein said animalenvironment is for a livestock animal, and wherein said animalenvironment is a building in which a livestock animal is reared.
 16. Theprocess according to claim 1, wherein said parasiticidal powdercomposition is introduced into said air introduction device in an amountper application of at least 5 mg per kg of animal.
 17. The processaccording to claim 1, wherein said parasiticidal powder composition isintroduced into the air introduction device in an amount per applicationof at most 2000 80 mg per kg of animal.
 18. The process according toclaim 1, wherein said parasiticidal composition is applied with afrequency of at least every two months.
 19. The process according toclaim 1, wherein said parasiticidal powder composition comprises atleast 1% silica, at least 60% alkali bicarbonate, and less than 30% ofwater; wherein said parasiticidal powder composition consists ofparticles; wherein said particles have a particle size distribution suchthat at least 75% in weight of the particles have a diameter of lessthan 100 μm; wherein said air introduction device comprises at least onepoint for introducing air into said animal environment, said at leastone introduction point being located close to animal droppings; whereinsaid parasiticidal powder composition is introduced into said airintroduction device in an amount per application of at least 5 mg and atmost 2000 mg per kg of animal, and wherein said parasiticidalcomposition is applied with a frequency of at least every two months.20. A device suitable for carrying out the process for controlling thedevelopment of parasites in an animal environment according to claim 1,comprising: at least one air duct for introducing outdoor air at atleast one point of introduction in said animal environment, at least oneappliance for forcing the circulation of air in said at least one airduct to produce in all or part of the at least one air duct an aircirculation velocity of at least 0.5 m/s, and at least one device ableto introduce an amount of at least 5 and at most 2000 mg/kg of animal ofa parasiticidal powder into said air duct upstream or downstream of saidat least one appliance for forcing air circulation.
 21. The deviceaccording to claim 20, wherein said appliance for the circulation of airflow in said at least one air duct is able to force the circulation ofair at a flow rate of at least 1 m³/h per kg of animal.